Potamiogeton.] clxx. naiadaob^. (J. D. Hooker.) 567 



long. Spike very short, few-fld. 5 flowers very small. Drupelets \ in., obliquely 

 ovoid, compressed, ribs entire or toothed. 



7. P. lucenS) Linn. Sp. PI. 126 ; stem stout, leaves large subsessile 

 oblong-lanceolate cuspidate undulate serrulate many-nerved, peduncle 

 stout thickened upwards, spike stout, drupelets small turgid shortly beaked. 

 Kunth Envm. iii. 132 ; Beichh. Ic. Fl. Germ. vii. t. 36, 37, 40 ; Boiss. Fl. 

 Vrient. v. 16. 



Kashmie, alt. 5-6000 ft., Jacguemont, Ac. Kumaon, alt. 6400 ft., Btrachey ^ 

 Winterbottom. — Distbib. N. temp, regions, Australia. 



Stem branched. Leaves 4-10 in., very variable, upper opposite sometimes float- 

 ing ; stipules large, long, 2-winged or -keeled. Drupelets -^ in., convex on both 

 faces, obtusely beaked. 



8. P. mucronatus, Presl Epimel. 245; leaves all submerged longer 

 than their petioles, elliptic- or oblong-lanceolate acute or cuspidate 

 membranous many-nerved base acute or obtuse, stipules much longer than 

 the petiole lanceolate connate, peduncle very long, spike of interrupted 

 groups or whorls of flowers. P. malaianus, Miq. HI. Fl. Archvp. Ind. 46. 

 P. lucens. Ham,, in Wall. Cat, 5176. 



Bengai ; at Dinagepore and Kulna and Karnata, Samilton. — Disteib. Borneo 

 Fbilipp. Islds. 



Lea/ees 3—5 by ^-^ in., 5—9 or more-nerved, blade twice or thrice as long as the 

 petiole ; stipules 1-1^ in. Spike 1^2 in. ; flowers laxly crowded or whorled. 

 Sepals suborbicnlar, very shortly clawed, frait -l-orbicnlar, shortly beaked. — Has a 

 good deal the aspect of P. Vacens, to which Hamilton referred it. The specimens 

 are very poor, and insufficient for a satisfactory diagnosis. 



*** Leaves all submerged, very narrowly linear or filiform. 



9. P. pectinatus, Unn. Sp. PI. 127 ; leaves filiform acute opaque 

 1-3-nerved, margins slightly thickened, stipules adnate to the leaf-sheath, 

 drupelets large turgid smooth hardly beaked. Kunth Fnum. iii. 137 ; 

 Reichh. Ic. Fl. Germ. vii. t. 19 ; Boiss. Fl. Orient, v. 18; Aitch. Oat. Panjal 

 PI. 145. P. marinus ?, Sam. in Wall. Cat. 5179 A, B in part. Buppia 

 subsessilis, Tkw. Enum. 383, in part. 



Plains of India, the Himalaya, and Westben and Eastern Tibet, alt. 12- 

 17,000 ft. CsTLOS, ThwaMes. — Disibib. most regions. 



Stem filiform, densely distichously branched. Leaves 3-8 by -^-1 in., lower 

 sometimes 5-nerved. VeS/vmcle not thickened upwards; flowers interruptedly 

 whorled. Drwpelets ^ in., dimidiate-obovoid. 



10. P. pusillus, Lmn. Sp. PI. 127 ; leaves narrowly linear or fiUform 

 acute usually 3-nerved membranous, stipules small free, peduncle long 

 filiform, flowers few minute clustered, drupelets turgid stoutly beaked 

 obtusely keeled. Kunth Errnvm. iii. 136 ; Reichb. Ic. Kl. Germ. vii. t. 22 ; 

 Boiss. Fl. Orient, v. 18 ; Wall. Cat. 5180. 



Eashmib, alt. 5000 ft., Thomson. — Distbib. !7. and S. temp, regions. 



Stem filiform, densely distichously branched. Leames i-3 in., rarely acuminate, 

 rarely 5-7-nerved. Spike 6-10-fld. Drupelets obliquely ovoid. 



Bahap. flaiellalms, Hook, f.. Students' Brit. Fl. 436; leaves -^ in. broad 3-5- 

 nerved. P. flabellatus, Bab. in Froc. Linn. 80c. Ser. ii. (1853), nom. ; in Pht/tolO' 

 gist, iv. 1158. P. marinus ? Ham. in Wall. Cat. 5179 B, in part. — Upper Bengal ; 

 Falaia, Wallich. The Fanjab, TJhomson. — Disteib. Britain. 



